Patent GB-678557-A (GB)
Title: Manufacture of aldehydes
IPC: C07C45/34
Filed: 1949-02-17
Abstract: A process for the production of unsaturated aldehydes comprises reacting an olefine of the general formula <FORM:0678557/IV (b)/1> in which R and R1 stand for hydrogen atoms or alkyl groups, with molecular oxygen by passing a gaseous mixture containing said olefine and oxygen at temperatures between 200 DEG  and 400 DEG  C. into contact with a solid contact material containing at least one metal or metal oxide other than copper or oxides of copper known to catalyse the oxidation of hydrocarbons in the gaseous state, in the presence in the reaction zone of elementary selenium.  Olefine starting materials mentioned are propylene, isobutylene, 2 - methylbut - 2 - ene, 2 : 4 : 4 - trimethylpent - 1 - ene, 2 : 4 : 4 - trimethyl - pent - 2 - ene, codimers of n-butene with isobutene and 2-methylpent-1-ene.  Catalytic metals mentioned are vanadium, iron, cobalt, nickel, manganese, chromium, molybdenum, tungsten, uranium, tin and cerium and the oxides thereof may also be used on supports such as pumice, asbestos, carborundum, silica and especially on silica gel and activated alumina.  The carriers may be impregnated with a solution or suspension of a salt or other compound of the catalytic metals which can be subsequently converted to the metal or oxide, e.g. by ignition.  The metals themselves may in general be obtained by passing a reducing gas or gases over the oxides on their supports.  The selenium may be introduced as selenium powder with the solid contact mass, or as a decomposable selenide, e.g. silver, antimony or cobalt selenide or selenium may be added to the reactant mixture before passing it over the catalyst.  Inert gases such as steam, carbon dioxide and nitrogen may be added to the gaseous mixture to prevent explosions.  The reacted mixture may be scrubbed to recover the product and if desired the residual gas may be recycled after replenishing the reactants.  Contact materials are prepared by treating activated alumina with (a) ammonium vanadate dissolved in hydrochloric acid; (b) ferric nitrate; (c) cobalt nitrate; (d) nickel nitrate; (e) manganese nitrate; (f) chromic acid, all in aqueous solution; (g) molybdic acid or (h) tungstic acid in aqueous ammonia; (i) uranium acetate dissolved in nitric acid; (j) a solution obtained by dissolving tin hydroxide precipitated from tin chloride with ammonia and by treating silica gel with boiling solutions of (l) ammonium uranate; (m) cobalt nitrate; (n) tungstic acid in aqueous ammonia; (p) nickel nitrate and drying and heat-treating the products.  In examples: (1) propylene-air mixtures are passed over heated selenium and through heated tubes containing vanadium, iron, manganese, chromium, uranium, tin and cerium on alumina; (3) and (4) propylene is similarly oxidized over uranium, cobalt, nickel, tungsten and molybdenum on silica gel and (2) isobutene is similarly oxidized over chromium, nickel, vanadium and iron on activated alumina.  Acrolein is obtained in examples (1), (3) and (4) and methacrolein in example (2). Specification 625,330 is referred to.ALSO:A solid contact material containing initially at least one metal or metal oxide other than copper or oxides of copper known to catalyse the oxidation of hydrocarbons is employed in the presence of selenium in the reaction zone in a process for the production of unsaturated aldehydes by the oxidation of an olefine of the general formula <FORM:0678557/III/1> in which R and R1 stand for hydrogen atoms or alkyl groups with molecular oxygen at temperatures between 200 and 400 DEG C (see Group IVb).  Metals mentioned are vanadium, iron, cobalt, nickel, manganese, chromium, molybdenum, tungsten, uranium, tin and cerium and the oxides thereof may also be employed.  The metals or metal oxides may be distributed on supports such as pumice, asbestos, carborundum and silica and especially silica gel and alumina.  The carriers may be impregnated with solutions or suspensions of compounds of the metals which may be converted into the metals or oxides e.g. the nitrates, carbonates and acetates, e.g. by ignition.  In general the metals may be obtained by passing hydrogen or a hydrogen containing or other reducing gas containing gas mixture over the oxides heated on their supports.  The contact material may be heat-treated.  Contact materials are prepared by treating activated alumina with (a) ammonium vanadate dissolved in hydrochloric acid (b) ferric nitrate (c) cobalt nitrate (d) nickel nitrate or (e) manganese nitrate or (f) chromic acid, in aqueous solution (g) molybdic acid or (h) tungstic acid in aqueous ammonia (i) uranium acetate dissolved in nitric acid (j) a solution in nitric acid of tin hydroxide precipitated from tin chloride with ammonia and by treating silica gel with boiling solutions of (1) ammonium uranate (m) cobalt nitrate (n) tungstic acid in aqueous ammonia (o) molybdic acid in aqueous ammonia (p) nickel nitrate and drying and heat treating the products.  In examples propylene or isobutene mixed with air is passed over heated selenium and then over the above heated contact materials to obtain the acrolein and methacrolein. Specification 625,330 is referred to.